Unusual Sites Disappearance

Show when searched with 20 or more results options

[webnewton]

This is something unusual which is being encountered with my site. These two sites of mine which were reigning the SERPS for the last 6 months on two very competitive keywords have suddenly disappeared. What is however surprising is:
1)These sites rank in top 10 when i search using 20 or more results option on Google.
2) Moreover while the sites are not visible for the main keyword say widgets they are still there on the top of SERPS for the secondary keywords say buy widgets or widgets online.
3)Another miscripency which i've noticed in the SERP results is that some of the newer results which are now showing are being repeated. This is strange.
4) Another thing thats strange about the results is that the SERPS are full of subdomain results. example

widgets.example.com
bluewidgets.example1.com
etc
Whats wrong with Gooogle?

[ciml]

It sounds like you could be busting a results cache by changing the search string slightly.

When the results are shifting, you tend to get one set of results consistently for a search. Then another when you change it slightly; sometimes even changing some seemingly irrelevant part of the search string such as the num value can do it. I find the -[made up word] approach helps.

Compare searches like these to get an idea of Google's results:
blue widget
blue widget -ksdhb
blue widget -ksdhb -ucsjb
blue widget -ksdhb -ucsjb -htvg

[frup]

I am experiencing the exact same phenomenon. I think it's a bug in google. It went away for a while then came back.

[webnewton]

It sounds like you could be busting a results cache by changing the search string slightly.

I know what you mean by this and indeed i tried searching using -asdfg etc but to no avail. Here again my result would show using the option for 20 or more results.
Also had this been the case my traffic wouldn't have suffered but it's reduced to 1/4th.
I checked out various datacenter results too. Only the ireland datacenter was showing my result in top 10 with the option of 10 results.

Well the breaking news is that my results have normalized this morning after those chaotic 8 days. So i am pleased but really can't get to the root of what happened. What if this happens again?

[frup]

My results normalized too.